.middle {
    display: flex;
    justify-content: center;
}

.middle > div {
    width: 900px;
    margin: 30px 0;
    /*padding: 30px;*/
    border: 1px solid gray;
}

/*--------------------在线留言----------------*/
.online-describe {
    display: flex;
    justify-content: center;
}

.online-describe > div > div:nth-child(1) {
    display: flex;
    justify-content: center;
    align-items: center;
}

.online-describe .font-title {
    font-size: 30px;
    color: rgb(230, 145, 55);
}